Local Air Quality Management
Guidance:
Low Emission Zones
February 2009
Contents
1 Introduction
1.1
1.5
1.6
Background and objectives of the guidance
Definitions
Economic rationale for LEZ Schemes
2 Options for LEZ uptake schemes
2.1
2.2
2.3
2.5
2.6
2.9
2.11
Scheme design
Legal basis for implementation
Traffic Regulation Orders
Planning conditions
Vehicle emissions standards
Management of permitted vehicles
Vehicle detection
3 Developing a Low Emission Zone
3.1
3.6
Emissions assessment
Costs assessment
4 Worked example
4.2
4.8
4.10
4.12
Do minimum or baseline case
Estimated effect of varying the emission standard to be achieved
Estimated effect of varying the implementation year
Conclusions
5 Examples of LEZ schemes
6 Conclusions
1 Introduction
Background and objectives of the guidance
1.1. This guidance is principally for local authorities in Scotland to assist in
carrying out their LAQM duties under Part IV of the Environment Act 1995. It
should be read in conjunction with the Scottish policy guidance PG(S)(09) and
the UK wide technical guidance TG(09).
1.2
The guidance provides information on:

establishing Low Emissions Zones (LEZs);

practical issues that have arisen in cases where LEZs have been
introduced;

evaluating costs and benefits of options in either cost-effectiveness or
cost-benefit analyses; and

examples of existing or planned schemes.
1.3
The guidance is advisory. Local authorities that have declared Air Quality
Management Areas (AQMAs) must have regard to the guidance when
developing their air quality action plans. However, the guidance is also
recommended to other local authorities that are considering implementing
measures to improve local air quality.
1.4
The guidance should be considered in conjunction with the revised policy
PG(S)(09) and technical TG(09) guidance, existing UK Government guidance
(the Green Book) and Transport Scotland’s Scottish Transport Appraisal
Guidance (STAG). Further advice can be obtained by contacting the Local
Authority Air Quality Action Plan Helpdesk (0870 190 6050 or
lasupport@aeat.co.uk)
Definitions
1.5
A Low Emission Zone (LEZ) is a geographically defined area where the
most polluting vehicles are restricted, deterred or discouraged from access and
use. LEZs have been successfully implemented and run for a number of years
in various places, for example Sweden, Japan, the Netherlands and, in the UK,
London. The impact can be similar to an acceleration of fleet turnover, thereby
reducing emissions sooner than would otherwise have happened. This guidance
considers enforceable restrictions of traffic and parking on public roads, and
planning conditions to control vehicle use and parking at private development
sites as a basis for setting up an LEZ.
Economic rationale for LEZ schemes
1.6
The economic rationale for LEZ schemes is linked to the external costs of
operating polluting vehicles, which place costs on society as a whole through
adverse health impacts and damage to ecosystems and the wider environment.
The separation of private transport benefits and public impacts means that
individuals are likely to consume goods or services in a way that is not socially
optimal, unless there is an intervention. Schemes described in this guidance
document seek to provide additional incentive in order to make progress towards
air quality objectives by reducing the external costs of transport.
1.7
LEZ schemes are focused on replacing the use of high emitting vehicles
with lower emitting ones. The main impacts of such schemes are likely to be:

Reduced emissions and improved air quality, hence contributing to
environmental, health and economic objectives;

Reduced consumer transport costs from using more efficient modes of
transport; and

Higher vehicle replacement costs, but overall improved fuel efficiency.
1.8
The ex ante appraisal of the London LEZ scheme suggested that progress
towards air quality objectives would be cost effective. As a result, three LEZ
policy scenarios were appraised during the 2007 revision of the Air Quality
Strategy to consider the wider application of such schemes. One scenario
assumed that LEZ schemes were implemented in seven large urban areas in the
UK, with a minimum Euro III standard introduced in 2010.
1.9
Benefits were estimated for the period 2010-2017. Emissions saved in
2010 were estimated at 150 tonnes PM10 and 461 tonnes NOx, diminishing to
zero by 2017. This was calculated to produce modest health benefits with a
present value of £5-7 million. The calculation did not take account of benefits
that may accrue outside of the LEZ zones. Scheme costs were estimated as a
present value of £9 million and costs to operators at £10 million, although with
high uncertainty for the latter. Schemes were assumed to be enforced via fixed
and mobile camera techniques. This guidance provides information on lower
cost options for implementing LEZ schemes.
1.10 In the Air Quality Strategy analysis the costs outweigh the benefits.
However, a Euro III standard would produce more benefits if it had been
implemented in 2008, as in the London scheme. For schemes implemented from
2010 onwards, local authorities should thus consider more stringent Euro
standards. The second phase of the London scheme will do this in order to
achieve air quality benefits in future years. In such cases the benefits are more
likely to match or exceed the costs.
2 Options for LEZ schemes
Scheme design
2.1
The starting point for the design of any LEZ scheme should be the
scheme objectives i.e. the targeted replacement of older vehicles. Having
established the objectives and identified potential locations for the zone, local
authorities should also consider:





Legal basis;
Enforcement powers and penalties;
Vehicle emission standards;
Management of permitted vehicles; and
Vehicle detection.
Legal basis for implementation
2.2
There are two main routes to setting up an LEZ with traffic or parking
controls based on vehicle emission criteria:

Traffic Regulation Orders (TROs) for enforceable restrictions on the
public highway; and

Planning conditions for development sites and private land.
Traffic Regulation Orders
2.3
There are several types of enforceable restrictions that can be employed
by local highway authorities under current legislation. The general basis for
these is the Traffic Regulation Order (TRO). TROs are commonly introduced to
manage traffic flow at specific locations, to define on street parking conditions, or
as part of a broader traffic management scheme. For example, TROs can be
used to restrict access to a given area for certain types or weight of vehicle
during specific time periods. More information on TROs is provided in the policy
guidance PG(S)(09) and the guidance note on encouraging uptake of low
emissions vehicles.
2.4
Advertising the TRO for an LEZ is an essential part of the scheme setup,
and guidance is provided in the relevant regulations about this and the statutory
consultees for any TRO. If a major LEZ is to be established then local authorities
should seek their own legal advice on the matter of advertising to vehicle owners
in other EU member states. Some European cities have used their membership
of the European LEZ Network (www.lowemissionzones.eu) to advertise their
information on vehicle emission standards.
Planning conditions
2.5
Planning conditions can be used to secure environmental benefits in new
developments. Further information can be found in the revised policy guidance
PG(S)(09).
Vehicle emission standards
2.6
The approach for defining LEV standards on which to base enforceable
restrictions (on the public highway or at development sites) could be determined
in one or a combination of ways. The following criteria are relevant to schemes
which target local pollutants:




Euro standards;
Age of vehicle/ year of first registration (year of first registration can be
taken as a proxy for Euro standard in almost all cases);
A particular fuel/technology combination; and/or
Engine size (as a proxy for fuel consumption, and hence CO 2 output).
2.7
Existing LEZs most commonly use Euro standards as the basis of their
schemes. Often, there are supplementary criteria to allow some exemption or
time extensions for retrofitting emission abatement technology. Age as a proxy
for Euro standard is also a common criterion. Further information on Euro
standards can be found in the guidance note on encouraging uptake of low
emission vehicles.
2.8
Retrofit technologies can assist vehicle owners who do not want, or
cannot afford, to buy a newer vehicle to comply with a scheme. For vehicles with
long lifetimes and high usage, such as buses, this can be more cost effective
than replacing the vehicle.
Management of permitted vehicles
2.9
In a large scheme covering a number of vehicle types, management will
probably require the creation of a database with links to the DVLA, as for the
London LEZ. For smaller schemes, affecting relatively few vehicles or one
focused on local fleets, a basic permit management and verification system may
be sufficient. Access control schemes in Cambridge and Bath are examples.
2.10 Management of permitted vehicles in a scheme based on a development
site should be more straightforward compared to public roads. Through traffic is
not usual and all vehicles are destined for privately controlled parking. The costs
of administering any scheme would be expected to be borne by the developer, or
ongoing management company set up by the developer or development
occupiers.
Vehicle detection
2.11 Identification of a vehicle that complies with scheme criteria could be via a
paper permit, windscreen sticker or the Vehicle Registration Mark (VRM) on the
number plate, or by self identification using a transponder or smart card.
Detection of a vehicle for subsequent identification of emission status could be
carried out by a variety of methods.
2.12 Manual methods usually involve enforcement personnel visually checking
vehicles travelling within or parked within the scheme area for identification
marks (VRM and/or a permit/sticker). In existing LEZs in Europe, checks
generally focus on older looking vehicles and might use a mixture of manual
recording and possibly photography. Some post checking against a database of
compliant vehicles is usually necessary.
2.13 Digital cameras and ANPR (automatic number plate recognition) record
passing number plates and use optical character recognition (OCR) for matching
against a vehicle database. A network of cameras can be installed on the key
routes in and out of the LEZ and possibly at key junctions within the zone if it is
large. ANPR cameras are able to capture 90%+ of passing number plates and
are used in the London Congestion Charge Scheme (CCS) and for the London
LEZ. In the London CCS, images are kept for checking of vehicles whose details
are not in the database of vehicles for which a charge has been paid or
registered as exempt. Mobile ANPR cameras can also be used to monitor key
junctions and/or hotspots.
2.14 Dedicated Short Range Communication (DSRC) tags and beacons are
more suitable for schemes with relatively few and/or predetermined users. Tags
or proximity smartcards are commonly issued to vehicle owners for accessing
private car parks, or can be scanned through a windscreen, and can also be
used to trigger bollards which control access on public roads.
2.15 The benefits of manual detection methods are lower capital costs and
some flexibility over future operating costs if enforcement levels can be reduced.
Manual enforcement is suitable for parking schemes, whether on street parking
or development sites. A drawback of manual enforcement is the limit on the
number and speed of vehicles that can be checked. However, evidence from
existing schemes shows this approach should not be ruled out.
2.16 The benefits of automated enforcement systems are that high speed and
volume flows of vehicles can be detected and recorded, and that every vehicle
can be checked. Drawbacks can include the relative inflexibility of fixed camera
systems once they are installed, and the upfront capital costs.
2.17 There will be additional options for identification and detection of vehicles
entering development sites, depending on the layout and approach for managing
traffic and parking. Such sites generally have a limited number of entry and exit
points, and are able to use manual or automatic barriers at these and at
entrances to car parks. The road network tends to discourage through
movement, and access by non residents or visitors. These factors enable
greater opportunity for checks on vehicles. Parking permit and management
systems provide opportunities for further identification and detection, to verify
against a permitted vehicle database.
3 Developing a Low Emission Zone
Emissions assessment
3.1
Local authorities are advised to use a staged process when assessing the
potential emissions and air quality impacts of a scheme. The initial stage should
be a screening assessment, the purpose of which is to quickly assess the
potential benefits of a scheme. At a basic level, LEV schemes are intended to
replace older vehicles with ones with more stringent emissions standards and are
thus aiming for a reduction in unit emissions.
3.2
A screening assessment could proceed as follows:






Define a zone inside which a LEV scheme might operate and identify
those vehicle types that the scheme would seek to regulate;
Assemble from transport models or otherwise estimate the annual
activity (veh km) of those vehicle types within the zone. One way of
estimating activity is to multiply traffic volumes by link length and then to
sum over all links in the zone;
Define a year in which the scheme may start;
Use the emissions factor toolkit for vehicle emissions
(www.airquality.co.uk/archive/laqm/tools.php?tool=emission) to obtain
the year and vehicle type specific emission factors for NOx and PM10
(g/veh km);
Multiply activity by emission factor to estimate the baseline emissions;
and
Recalculate the product of the activity and the emission factors to
estimate the annual emissions with the scheme in operation.
The difference from the baseline is the potential emissions benefit of the scheme.
3.3
This simple approach to assessing LEV schemes does not address
potentially important effects such as the redistribution of traffic and the
contribution to emissions from congested conditions. Intermediate or detailed
assessments will address these issues more fully. For an intermediate
assessment local authorities should refer to the revised technical guidance
TG(09) and the guidance document on economic principles for assessment of
local air quality schemes. These provide background information on developing
a detailed baseline emission inventory and available tools for estimating the
emission impacts of transport measures. An inventory should be sufficiently
detailed to allow the impacts of a range of potential policies to be assessed,
accounting for:

The impacts of national policies such as Euro standards for vehicle
emissions;




The impacts of local transport policy on traffic growth and other actions
to which the local authority is already committed including transport
policies and new developments;
Road transport activity potentially disaggregated by zone and vehicle
type, allowing the effects of policies that reduce activity, move its
location or switch from one transport mode to another;
The contribution from stationary traffic, allowing policies that reduce
congestion; and
Fleet numbers and ages for key vehicle types, allowing the effects of
policies to promote the uptake of newer vehicles.
3.4
Potential sources of data from which to develop emission inventories
include road transport models, which can provide average speed and annual
average daily flow data disaggregated by road link and usually split between light
and heavy duty vehicles. More detailed surveys have been used to disaggregate
HDV types between buses and heavy goods vehicles. Furthermore, some traffic
models also provide link specific data on the daily average time that traffic is
stationary at junctions and the average length of these queues. These data are
necessary to estimate the potential contribution from congestion. Also of use is
the emissions factor toolkit allows calculation of road traffic exhaust emissions for
different vehicle categories and splits, at various speeds, and on different road
types, besides calculating emission factors in future years.
3.5
In the case of specific and relatively small fleets (such as the local
authority’s own fleet or commercially operating bus fleets) it is recommended that
a specific fleet inventory is developed. A key reason for this is that the
distribution of vehicle ages within these fleets can typically vary quite significantly
from the national average age distribution. For example, the local bus fleet may
be significantly older or younger than the national average. For better accuracy it
is therefore recommended to list the age and abatement equipment of each
vehicle. Air quality assessments use monitoring, dispersion modelling and GIS
data to assess where the air quality objectives are exceeded and whether there
is relevant exposure at these locations. The methods to be used in these
assessments are provided in detail in the revised technical guidance TG(09).
Costs assessment
3.6
Basic information on costs assessment can be found in the guidance note
on encouraging uptake of low emissions vehicles. More detailed information on
cost effectiveness and cost benefit analysis is in the guidance note on economic
principles.
4 Worked example
Introduction
4.1
The following worked example illustrates how this guidance may operate
in practice. It assumes an LEZ is implemented to regulate HGV emissions via
replacement of existing vehicles with new ones. The example illustrates the
effect of varying the emission standard with and year by which the HGVs must
comply.
Do minimum or baseline case
4.2
This policy affects HGVs only. The first step is to collate information on:



Number of vehicles potentially affected;
Their age (i.e. when first registered) and whether they already have
abatement equipment fitted; and
Planned replacement rates (i.e. how long each is expected to remain in
service).
4.3
HGVs and their activity is mainly unregulated by local authorities. Unlike
buses there are potentially many different operators and vehicles involved, so it
is unlikely that fully comprehensive and accurate data will be readily available. It
will therefore be necessary to rely on the predictions in the Air Quality Archive,
using the vehicle emissions factor toolkit:
http://www.airquality.co.uk/archive/laqm/tools.php?tool=emission or NAEI web
pages to obtain the year and vehicle type specific emission factors for NO x and
PM10 (g/veh km). These emission factors take account of the weighted
contribution of different Euro standard vehicles to the average emission factor
based on UK data covering vehicle replacement rates. The following two tables
illustrate this approach.
Proportionate breakdown of national HGV fleet by Euro standard
Vehicle
Standard
2007 2008
2009
2010
2011
2012
2013
2014
2015
Rigid
HGV
Rigid
HGV
Rigid
HGV
Rigid
HGV
Rigid
HGV
Rigid
HGV
Pre-Euro
I
Euro I
0.004
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.054
0.033
0.015
0.006
0.000
0.000
0.000
0.000
0.000
Euro II
0.294
0.237
0.187
0.138
0.098
0.066
0.035
0.016
0.006
Euro III
0.510
0.474
0.428
0.392
0.332
0.274
0.219
0.170
0.123
Euro IV
0.137
0.230
0.232
0.207
0.195
0.189
0.170
0.146
0.119
Euro V
0.000
0.027
0.137
0.257
0.375
0.471
0.575
0.667
0.751
Artic
HGV
Artic
HGV
Artic
HGV
Artic
HGV
Artic
HGV
Artic
HGV
Total
Pre-Euro
I
Euro I
1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000
0.002
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.000
0.027
0.018
0.009
0.003
0.000
0.000
0.000
0.000
0.000
Euro II
0.210
0.149
0.101
0.069
0.051
0.035
0.021
0.010
0.003
Euro III
0.587
0.518
0.441
0.360
0.274
0.201
0.143
0.098
0.067
Euro IV
0.175
0.280
0.274
0.253
0.226
0.195
0.160
0.126
0.093
Euro V
0.000
0.035
0.175
0.316
0.449
0.569
0.675
0.765
0.837
Total
1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000
Baseline HGV emission factors (g/km) at 30kph based on national fleet
trends
2007 2008 2009 2010
5.388 5.000 4.527 4.097
NOx
Rigid
HGV
NOx 11.77 10.79 9.55
8.47
Artic
HGV
PM10 0.142 0.121 0.105 0.091
Rigid
HGV
PM10 0.38
0.32
0.27
0.22
Artic
HGV
2011
3.702
2012
3.386
2013
3.073
2014
2.821
2015
2.612
7.57
6.80
6.16
5.62
5.23
0.078
0.068
0.058
0.050
0.044
0.19
0.16
0.13
0.11
0.10
4.4
This example takes a simplified view that an average speed of 30kph is
representative of urban HGV activity. Detailed analysis should include
consideration of emissions associated with congestion and other relevant factors.
It is also necessary to collate estimates of the total annual vehicle kilometres
travelled by these vehicles. These data are most likely to be held in local
datasets such as local authority traffic models. If the policy will only be enforced
in a specific zone, the total annual vehicle kilometres travelled by HGVs in that
zone should be estimated. This can be done by multiplying the total link length
on the implicated routes by the annual traffic flow.
Baseline HGV activity data (million veh.km)
Rigid
HGV
Artic
HGV
2007
44.13
2008
43.69
2009
43.25
2010
42.81
2011
43.01
22.29
22.88
23.48
24.08
24.45
2012
43.20
2013
43.40
2014
43.60
2015
43.79
24.83
25.20
25.58
25.95
4.5
Emission rates and activity data are multiplied to estimate the baseline
HGV emissions.
Estimated baseline HGV emissions (tonnes) in the LEZ
2007
2008
2009
2010
2011
2012
2013
2014
2015
255.2
233.6
209.0
186.7
168.1
153.4
138.6
126.7
116.9
262.33
246.84
224.29
203.92
185.03
168.92
155.15
143.85
135.69
517.49
480.44
433.32
390.64
353.17
322.29
293.73
270.54
252.55
7.1
6.0
5.1
4.4
3.7
3.2
2.7
2.3
2.0
8.43
7.34
6.29
5.37
4.56
3.89
3.34
2.91
2.62
15.55
13.35
11.40
9.76
8.29
7.09
6.05
5.23
4.63
NOx - Rigid
HGV
NOx - Artic
HGV
NOx total
PM10 Rigid HGV
PM10 Artic HGV
PM10 total
Estimated effect of varying the emission standard to be achieved
4.8
The baseline HGV fleet can be analysed for realistic options for setting
future emission standards. Between 2008 and 2011 the majority of vehicles are
of Euro III standard or better. Therefore the objective of an LEZ during this
period may be for all vehicles to achieve this standard. From 2011 onwards the
contribution of Euro III vehicles is in decline, thus an LEZ scheme should take
this into account.
4.9
From 2008 onwards Euro V standard vehicles are increasingly available.
Theoretically it would be possible for a fleet operator to buy vehicles second-
hand if they are compliant with whatever euro standard is selected as the criteria
for a scheme, but this example assumes that replacement is always to a new
vehicle. The tables below illustrate the changes to the baseline HGV fleet and
emissions that would occur if the fleet had by 2010 to achieve a:



Euro III standard (requires all pre-Euro III vehicles to be replaced);
Euro IV standard (requires all pre-Euro IV vehicles to be replaced); and
Euro V standard (requires all pre-Euro V vehicles to be replaced).
The tables include a calculation of the difference in annual emissions relative to
the base case.
Euro III standard
Rigid
HGVs
Euro I
Euro II
Euro III
Euro IV
Euro V
Total
Emission
rate
2007
2008
2009
2010
2011
2012
2013
2014
2015
0.29
0.51
0.14
0.00
1.00
0.03
0.24
0.47
0.23
0.03
1.00
0.02
0.19
0.43
0.23
0.14
1.00
0.00
0.00
0.39
0.21
0.40
1.00
0.00
0.00
0.33
0.19
0.47
1.00
0.00
0.00
0.27
0.19
0.54
1.00
0.00
0.00
0.22
0.17
0.61
1.00
0.00
0.00
0.17
0.15
0.68
1.00
0.00
0.00
0.12
0.12
0.76
1.00
NOx
(g/km)
PM
(mg/km)
Emissions
(tonnes)
5.78
5.35
4.83
3.59
3.39
3.20
3.00
2.82
2.63
0.16
0.14
0.12
0.08
0.07
0.06
0.06
0.05
0.04
NOx
PM10
Artic
HGVs
Euro I
Euro II
Euro III
Euro IV
Euro V
Total
Emission
rate
255.16
7.12
2007
233.60
6.02
2008
209.04
5.12
2009
153.56
3.27
2010
145.60
2.98
2011
138.22
2.70
2012
130.38
2.43
2013
122.91
2.20
2014
115.36
1.96
2015
0.027
0.210
0.587
0.175
0.000
1.00
0.018
0.149
0.518
0.280
0.035
1.00
0.009
0.101
0.441
0.274
0.175
1.00
0.000
0.000
0.360
0.253
0.39
1.00
0.000
0.000
0.274
0.226
0.50
1.00
0.000
0.000
0.201
0.195
0.60
1.00
0.000
0.000
0.143
0.160
0.70
1.00
0.000
0.000
0.098
0.126
0.78
1.00
0.000
0.000
0.067
0.093
0.84
1.00
NOx
(g/km)
PM
(mg/km)
Emissions
(tonnes)
11.77
10.79
9.55
7.63
6.98
6.41
5.91
5.51
5.19
0.38
0.32
0.27
0.19
0.16
0.14
0.12
0.11
0.10
NOx
PM10
Emissions
(tonnes)
262.33
8.43
246.84
7.34
224.29
6.29
183.73
4.55
170.72
3.98
159.12
3.49
149.04
3.10
140.87
2.79
134.74
2.58
Total NOx
Total PM10
Difference
from
Baseline
(tonnes)
Total NOx
517.49
15.55
480.44
13.35
433.32
11.40
337.29
7.82
316.32
6.97
297.34
6.19
279.41
5.53
263.78
4.99
250.10
4.55
0.00
0.00
0.00
53.35
36.85
24.95
14.32
6.76
2.44
0.05
Total PM10
0.00
0.00
0.00
1.93
1.32
0.89
0.52
0.24
0.09
Euro IV standard
Rigid
HGVs
Euro I
Euro II
Euro III
Euro IV
Euro V
Total
Emission
rate
2007
2008
2009
2010
2011
2012
2013
2014
2015
0.05
0.29
0.51
0.14
0.00
1.00
0.03
0.24
0.47
0.23
0.03
1.00
0.02
0.19
0.43
0.23
0.14
1.00
0.00
0.00
0.00
0.21
0.79
1.00
0.00
0.00
0.00
0.19
0.81
1.00
0.00
0.00
0.00
0.19
0.81
1.00
0.00
0.00
0.00
0.17
0.83
1.00
0.00
0.00
0.00
0.15
0.85
1.00
0.00
0.00
0.00
0.12
0.88
1.00
NOx
(g/km)
PM
(mg/km)
Emissions
(tonnes)
5.78
5.35
4.83
2.40
2.38
2.37
2.34
2.30
2.26
0.16
0.14
0.12
0.03
0.03
0.03
0.03
0.03
0.03
NOx
PM10
Artic
HGVs
Euro I
Euro II
Euro III
Euro IV
Euro V
Total
Emission
rate
255.16
7.12
2007
233.60
6.02
2008
209.04
5.12
2009
102.58
1.30
2010
102.22
1.30
2011
102.30
1.31
2012
101.50
1.32
2013
100.34
1.32
2014
98.96
1.33
2015
0.027
0.210
0.587
0.175
0.000
1.00
0.018
0.149
0.518
0.280
0.035
1.00
0.009
0.101
0.441
0.274
0.175
1.00
0.000
0.000
0.000
0.253
0.75
1.00
0.000
0.000
0.000
0.226
0.77
1.00
0.000
0.000
0.000
0.195
0.80
1.00
0.000
0.000
0.000
0.160
0.84
1.00
0.000
0.000
0.000
0.126
0.87
1.00
0.000
0.000
0.000
0.093
0.91
1.00
NOx
(g/km)
PM
(mg/km)
Emissions
(tonnes)
11.77
10.79
9.55
5.29
5.20
5.10
4.98
4.87
4.76
0.38
0.32
0.27
0.08
0.08
0.08
0.08
0.08
0.08
NOx
PM10
Emissions
(tonnes)
262.33
8.43
246.84
7.34
224.29
6.29
127.36
1.90
127.09
1.93
126.57
1.96
125.50
1.99
124.49
2.02
123.45
2.05
Total NOx
Total PM10
Difference
from
Baseline
(tonnes)
Total NOx
Total PM10
517.49
15.55
480.44
13.35
433.32
11.40
229.93
3.20
229.31
3.24
228.87
3.27
227.00
3.31
224.83
3.35
222.41
3.38
0.00
0.00
0.00
0.00
0.00
0.00
160.70
6.56
123.87
5.05
93.43
3.81
66.73
2.74
45.71
1.89
30.14
1.25
2007
2008
2009
2010
2011
2012
2013
2014
2015
0.05
0.29
0.51
0.14
0.00
0.03
0.24
0.47
0.23
0.03
0.02
0.19
0.43
0.23
0.14
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
1.00
0.00
0.00
0.00
0.00
1.00
Euro V standard
Rigid
HGVs
Euro I
Euro II
Euro III
Euro IV
Euro V
Total
Emission
rate
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
NOx
(g/km)
PM
(mg/km)
Emissions
(tonnes)
5.78
5.35
4.83
2.07
2.07
2.07
2.07
2.07
2.07
0.16
0.14
0.12
0.03
0.03
0.03
0.03
0.03
0.03
NOx
PM10
Artic
HGVs
Euro I
Euro II
Euro III
Euro IV
Euro V
Total
Emission
rate
255.16
7.12
2007
233.60
6.02
2008
209.04
5.12
2009
88.79
1.30
2010
89.20
1.30
2011
89.59
1.31
2012
90.01
1.32
2013
90.42
1.32
2014
90.82
1.33
2015
0.027
0.210
0.587
0.175
0.000
1.00
0.018
0.149
0.518
0.280
0.035
1.00
0.009
0.101
0.441
0.274
0.175
1.00
0.000
0.000
0.000
0.000
1.00
1.00
0.000
0.000
0.000
0.000
1.00
1.00
0.000
0.000
0.000
0.000
1.00
1.00
0.000
0.000
0.000
0.000
1.00
1.00
0.000
0.000
0.000
0.000
1.00
1.00
0.000
0.000
0.000
0.000
1.00
1.00
NOx
(g/km)
PM
(mg/km)
Emissions
(tonnes)
11.77
10.79
9.55
4.45
4.45
4.45
4.45
4.45
4.45
0.38
0.32
0.27
0.08
0.08
0.08
0.08
0.08
0.08
NOx
PM10
Emissions
(tonnes)
262.33
8.43
246.84
7.34
224.29
6.29
107.06
1.90
108.70
1.93
110.39
1.96
112.03
1.99
113.72
2.02
115.37
2.05
Total NOx
Total PM10
Difference
from
Baseline
(tonnes)
Total NOx
Total PM10
517.49
15.55
480.44
13.35
433.32
11.40
195.84
3.20
197.90
3.24
199.98
3.27
202.04
3.31
204.15
3.35
206.19
3.38
0.00
0.00
0.00
0.00
0.00
0.00
194.80
6.56
155.27
5.05
122.31
3.81
91.69
2.74
66.39
1.89
46.36
1.25
Estimated effect of varying the implementation year
4.10 The baseline HGV data can be analysed to set the year by which
standards should be achieved. In this example it is assumed that the emission
standard to be achieved is Euro III (i.e. all pre-Euro III vehicles are replaced.)
From the tables it can be seen that the 2010 compliance date will affect around
15% of rigid HGV and 7% of articulated vehicles, the 2012 date would affect 7%
of rigid HGV and 3.5% of articulated vehicles, whereas the 2015 date will affect
only <1% of rigid HGV and <1% of articulated vehicles due to the predicted
natural replacement rate of vehicles over this period. It thus follows that
compliance with the 2012 and 2015 dates would cost operators less but would
also have a lesser effect. This illustrates the important point that setting an early
compliance date will achieve more local air quality and emission benefits but
usually at higher costs.
4.11 The 2010 implementation date would deliver several years of benefits
relative to the base case, whereas the 2012 case would deliver fewer benefits
and for a shorter period. As time passes the gap between the base case and the
Euro III standard decreases due to natural replacement of older vehicles. By
2015 the benefits due to the Euro III standard is very small.
Conclusions
4.12 In terms of emissions and air quality benefits the main points to be
considered for any vehicle replacement policy are:




to set an appropriate emission standard to achieve an outcome where
there are local emissions reductions relative to the base case. The
higher the Euro standard the bigger the potential reductions;
to set an appropriate implementation year to achieve an outcome where
there are local emissions reductions relative to the base case; earlier is
better;
to consider setting further Euro standards and implementation years (i.e.
subsequent phases of emission reduction) otherwise the benefits of the
policies will be eroded over time by natural vehicle replacement rates;
and
the emission standards and implementation years have to be balanced
against costs, but also the level of action required to achieve the air
quality objectives.
5 Examples of LEZ schemes
5.1
Traffic control schemes are common in UK towns and cities. Some
schemes in the UK have either been designed to include emission criteria or
have been considered for such a modification, and can be viewed as small scale
examples of LEZs.
5.2
Examples of larger LEZs are shown in the following table:
Scheme
Basis
Area
Vehicles
Standards
(retrofit/incentives)
Enforcement
Sweden Environmental
Zone
Traffic
restriction
City centres
or key
districts
HDV (HGV
and bus)
HGV: age limit of 6
years. Allowance for
trucks between 6
and 8 years old if
retrofitted for PM
Manual
enforcement
by Police.
Scheme
applies to
foreign
vehicles
Greenwich
Peninsula
Planning
Condition
190 acres of
development
site
All vehicles
Various, depending
on land-use and
vehicle type. Based
on Euro standards
Bath - PAS
Traffic
restriction
1 key route
through
centre
Priority/access
for bus and
taxi, plus a
few permitted
Goods
Vehicles
Free access to bus
and taxi.
Supermarket
delivery vehicles
must be of latest
Euro standard
Non
compliance
will be a
breach of
planning
control
Manual, by
Police.
Vehicles
without
transponders
cannot
trigger green
light to pass
through
access point
Milan EcoPass
Charge
City centre
All vehicles
Charge related to
level of PM
emissions. Cleanest
diesel and petrol
vehicles gain free
entry
43 entrance
points with
CCTV and
ANPR
cameras.
Penalty is
75€ to 275€
depending
vehicle size
London - LEZ
Charge
Greater
London
HDV (HGV,
Coach etc),
with heavy
vans to be
added later
From 4th Feb. 2008,
a standard of Euro 3
for particulate
matter (PM) for
lorries over 12
tonnes Gross
Vehicle Weight
(GVW), and buses
and coaches over 5
tonnes GVW.
• From July 2008, a
standard of Euro 3
Large
network of
ANPR
cameras.
Penalty for
noncompliance
and nonpayment is
£500/£1000
depending on
vehicle size
Mgt of
permitted
vehicles
Sticker
permits
denote
compliant
vehicles.
Retrofit for
PM possible
for narrow
age band
To be
confirmed.
Retrofitting of
HDV possible
for PM
Comments
Bus, taxi,
permitted
Goods
Vehicle apply
for
transponders.
Simple
addition of
environmental
criteria to
ensure high
standards
from nonpublic
transport
vehicles.
Enforcement
depends on
police support
Reduces
congestion
and
emissions.
Revenue can
be used to
improve
transport.
Complex
scheme rules
with variety of
passes
Daily and
multiday/annual
passes can
be
purchased.
Cost based
on Euro
standards.
Alternative
fuels and
retrofit for PM
possible
Compliant
vehicles selfregistered via
number plate
and DVLA
records. Nonstandard
cases and
retrofit
vehicles
required to
register
Age based
system is
relatively
simple
Management
and operation
is
responsibility
of developer
Phased
approach to
ensure
tightening
emission
standards
Netherlands LEZ
(Milieuzone)
Traffic
restriction
Central city
areas
HGV
German LEZ
(Umweltzone)
Traffic
restriction
Central city
areas
All vehicles
for PM for lorries
between 3.5 and 12
tonnes, buses and
coaches
• From Oct. 2010, a
standard of Euro 3
for PM for larger
vans and minibuses
• From January
2012, a standard of
Euro 4 for PM for
lorries over 3.5
tonnes GVW, buses
and coaches over 5
tonnes GVW.
• Min standard of
Euro 2 and 3 plus
particulate filter or
Euro 4 will be in
force up until 1 Jan.
2010
• Between 1 Jan.
2010 and 1 July
2013 the minimum
standard will be less
than 8 years or Euro
3 plus PM filter;
• After 1 July 2013
the minimum
standard is Euro 4
Vehicle owners
required to
purchase stickers
(20 €) stating
environmental
standard. Each LEZ
signs which is
minimum
sticker/standard
required for access.
Standards tougher
for diesel vehicles
vehicle. Daily
charge
(£200) for
vehicles who
do not
comply.
Retrofit for
PM possible.
Manual, plus
some
(increasing
number of)
ANPR
camera.
Penalty is
150€
Retrofit for
PM possible
Phased
approach to
ensure
tightening
emission
standards
Manual
enforcement.
40 € fine plus
1 point in
national
traffic penalty
register for
German
vehicles
Stickers
denote
emission
level of all
relevant
vehicles.
Sticker must
be show if
vehicle to be
driven in any
LEZ.
Certification
system for
retrofit
vehicles.
Retrofit for
PM (cars and
HGV)
possible
Flexible
framework for
cities to
choose from
emission
standards.
Includes cars
and
encourages
PM retrofitting
6 Conclusions
6.1
A range of schemes can be developed by local authorities to directly
influence the emission standards of vehicles, using traffic and parking restrictions
and development control schemes. Schemes restricting traffic on public roads
are closest to the general concept of an LEZ.
6.2
The London LEZ is a charge based scheme, with exemptions for the
cleanest vehicles. Many of the functions and processes required for setting up
and operating the scheme are the same, whether the basis is a restriction on a
vehicle or a charge. Experience suggests that elements of the scheme design
could be replicated elsewhere.
6.3
A range of current LEZs based on traffic restrictions show that key
variables in schemes are:





scheme size and land use;
vehicle types;
emission standards and pollutant types;
management of permitted vehicles; and
vehicle detection and enforcement methods.
6.4
Such LEZs tend to be found in city and town centres, where land use is
dense, traffic is heavy and population exposure is high. There is the highest
value in such areas from restricting, discouraging or deterring the use of more
polluting vehicles. Source apportionment should be used to determine which
vehicles and which pollutants are the most relevant to target. This should be
considered as part of the scheme design, to determine the cost-effectiveness of
various options.
6.5
From existing examples, the most common vehicles to target in a scheme
with enforceable restrictions are HDVs (and bus fleets in particular) due to their
cost-effectiveness, relative to schemes that would restrict other vehicle types.
The most common air pollutant to target is PM. HDVs produce higher levels of
emissions than lighter, smaller engined vehicles and the options for retrofitting
are better developed and more cost effective for PM than for NOx.
6.6
A scheme that encompasses a greater variety of vehicles will generally be
more costly to set up and administer, therefore in value for money terms it is
more cost effective to target those vehicles with the highest overall emission
contribution first (e.g. bus fleets with large urban centre activity), which is also
where any grants or subsidies for retrofitting should be aimed.
6.7
Diesel vehicles tend to produce higher levels of PM emissions than the
equivalent petrol vehicle, and reduction in PM emission generates significant
levels of health benefits.
6.8
The worked example shows that schemes should aim to regulate
emissions to a sufficiently high standard and early enough to produce benefits
over and above the business as usual case. Between now and 2010-2012 a
Euro III standard should be considered as the for LEZ schemes. From 20102012 onwards, higher standards should be considered.
6.9
Similar standards within a country are useful, but not essential to setting
up and operating a LEZ. A common framework, with local authorities free to
choose their own standard is a possible approach (used in Germany). A
common set of standards across all vehicles, with authorities choosing which
vehicles from the framework to include in their scheme and how to enforce it is
another alternative. When choosing standards, co-operation between
neighbouring authorities is advised.
6.10 The most effective methods of managing permitted vehicles (for traffic,
parking or development control schemes) will be to use existing systems and
sources of information as far as possible. Nevertheless, existing systems will
probably not provide a complete solution and new systems and processes may
be required. There may need to be some tradeoff between the optimum
operation of a scheme (for emission reduction and cost) against ease of use and
acceptance.
6.11 Given financial constraints, a scheme which has low operating costs will
tend to be more attractive from a whole lifecycle viewpoint. However, this needs
to be carefully balanced against the resulting level of compliance by users, or the
purpose and value of the scheme is undermined.
6.12 Small areas, road networks with limited access points, and areas with
existing traffic restrictions (e.g. pedestrian zones) can be used for LEZs at
relatively low cost and may be the most cost effective areas to tackle first.